The deadline has passed for pro-Russian militants to lay down their weapons in Eastern Ukraine. Now everyone is waiting to whether the government will keep its promise to reclaim occupied towns by force. Ukraine's president says the military is ready to stage a large-scale assault today.

NPR's Ari Shapiro is in the Eastern Ukrainian city of Donetsk and joins us on the line. Ari, good morning.

ARI SHAPIRO, BYLINE: Hi, David.

GREENE: So this sounds like over the weekend things became much, much more intense in this part of Ukraine where you're reporting. Tell us exactly what happened.

SHAPIRO: Yeah, on Saturday, armed men in camouflage took over government buildings in several cities throughout Eastern Ukraine near the Russian border. These were highly coordinated, highly professional-looking efforts. It was a far more intense and militaristic takeover than the occupations that we saw in this region a week ago. In the city of Slavyansk, for example, the occupiers set up roadblocks, basically taking over the city.

And the next day, on Sunday morning, the government responded forcefully with what it called an anti-terror operation in the city of Slavyansk. In the process, people were killed on both sides - which is the first bloodshed in this standoff. And then last night Ukraine's president basically said enough is enough, the blood of Ukrainian heroes has been spilled. He set this deadline, saying if you don't put down your weapons by Monday morning we will send in the military.

GREENE: OK. So Monday morning where you are has now come and gone. This deadline has passed. I mean do you get any sense for what the government is planning here?

SHAPIRO: There's a real tension in the air here. I'm going to play you a bit of President Turchynov statement last night. This is what he said to the country.

PRESIDENT OLEKSANDER TURCHYNOV: (Foreign language spoken)

SHAPIRO: He's saying the Security Council of Ukraine decided to start an anti-terrorist operation with the use of the Ukrainian Army. We will not let Russia repeat the Crimean scenario.

TURCHYNOV: (Foreign language spoken)

SHAPIRO: The government, of course, is referring to Russia's annexation of the Crimea Peninsula. They see the same scenario playing out here in the East. Turchynov says up to 12,000 troops could come here to take control of the region.

And keep in mind, David, this would mean sending armed forces into Ukrainian cities that are already suspicious, even antagonistic towards Kiev. It could mean shooting and killing Ukrainians citizens, even little old ladies, who the protesters used in Slavyansk yesterday to reinforce roadblocks. So this could all be extremely volatile, to say the least.

GREENE: Oh, these are the babushkas, the elderly women who you've reported have sort of been used...

SHAPIRO: Yeah, these are some pretty militant women who I experienced first hand, speaking to over the last week.

GREENE: So human shields in a way, but it seems like they're there willingly.

SHAPIRO: Absolutely.

GREENE: Well, Ari, Ukraine blames Russia. They keep saying that this is Russia orchestrating this. I mean has Moscow given a response to that?

SHAPIRO: Yeah, Russia's foreign minister described the Ukrainian government's plans as criminal and says these protests are an authentic reaction to the oppression of Russian speakers in the east of Ukraine. Russia asked the West to intercede to stop this. And Russian television last night broadcast a statement by the ousted former President of Ukraine - who is close with Russia - Viktor Yanukovych. He is taking refuge in Russia right now. And here's part of Yanukovych's statement.

VIKTOR YANUKOVYCH: (Foreign language spoken)

SHAPIRO: He says: Our country now is in a completely new situation. Ukraine actually has one foot in a civil war.

GREENE: Well, you're in Donetsk, a major city Eastern Ukraine. Does it feel like a civil war?

SHAPIRO: Well, the fog here is so thick this morning we can actually barely see across the street. It is like a literal manifestation of the Fog of War. But we have spoken to people around the region this morning. A police officer here in Donetsk tells us things are quiet but everyone is very tense. A woman who lives closer to the Russian border, near the city of Luhansk, says it feels like a civil war already where she is, with Ukrainians beating up other Ukrainians. She may be referring to a clash yesterday in the town of Mariupol, where a group of pro-Russian demonstrators and a group of pro-Western demonstrators literally started beating each other up.

And then, of course, in Slavyansk - where yesterday protesters and special forces were shooting at each other - schools today are closed and the streets are nervously quiet.

GREENE: And we should say this is still at a moment when there are Russian troops gathered right across the border - everyone watching to see if they are going to make some kind of move.

SHAPIRO: Right, they cast a long shadow here. From the beginning, Ukraine has accused Russia of stirring up these protests as a pretext for invasion. Now that the protests have turned into violent clashes, the question is whether those Russian tanks - less than 100 miles from here - will come across the border in order to, as the Russian government would describe it, defend the lives of Russian speakers in Ukraine.

GREENE: Alright, that's NPR's Air Shapiro, who is reporting on a very tense situation in Eastern Ukraine in the city of Donetsk. Ari, thanks a lot.